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Beacon-based sleep status and physical activity monitoring in humans

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Abstract

One out of every five people in Japan is dissatisfied with their sleep and various diseases caused by lack of exercise have been pointed out, but there are few effective remedies for these problems. In this study, we aimed to develop a simple method for measuring behavioral sleep patterns and physical activity using a beacon accelerometer wirelessly connected with a smartphone. A sleep prediction model was created comparing the data obtained from the accelerometer with the sleep status data obtained by a previously validated sleep monitoring system. The Random Forest model was able to classify sleep and wakefulness with a 97.4% and 85.4% precision, respectively, which were comparable to those of conventional acceleration-based sleep monitoring devices. Additionally, the same data acquisition method was used to classify exercise intensity into seven levels and a high correlation (r=0.813, p<0.0001) was found when comparing the classified exercise intensity to metabolic equivalent (MET) values. This suggests that the proposed method can be used for accurate measurement of both behavioral sleep and physical activity classifying over a long period of time.

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... Devices and a data processing procedure followed our previous method used in human study [11]. In brief, a Bluetooth beacon accelerometer (MetamotinRL, Mbientlab Co. Ltd., CA, USA), an Android smartphone (Aquos Sense2, SHARP, Co, ltd, Tokyo, Japan), and Omron Sleep Meter HSL-102-M (Tokyo, Japan) were used. ...
... The three axes of the acceleration values were combined into a scalar value, which was then averaged over a one-sec interval. Following the previously reported procedure [11], standard deviation (SD) values of the scalar amount of acceleration per sec were calculated every 30 sec. The subsequent analysis involved utilizing five consecutive variables of SD data: two data points from one min before and two data points from one min after the target epoch. ...
... SAS Institute. Ltd, Cary, NC, USA), as reported previously [11], because it is based on probabilities of cluster membership rather than arbitrary cluster assignments based on boundaries. Regarding the number of clusters, we chose 7 clusters to facilitate comparison with metabolic equivalent of task (MET) scale in humans. ...
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